A report from Stratfor mentions Chinese Intelligence using cell phone jamming on protestors and also using imitative communications deception (Via the Australian Financial Review). Quote:

In addition to the intelligence collection efforts and the careful organization and coordination of the pro-China demonstrators in San Francisco, electronic countermeasures also were used to disrupt the communications and activities of the anti-China demonstrators. In some cases, the cell phones of the anti-China organizers were spammed with prank calls and text messages in order to limit their effectiveness as a coordinating tool — particularly as the torch changed routes. There also were unconfirmed cases of limited cell-phone jamming, likely using the short-range cell-phone jammers that were popular a few years ago. These created intermittent and isolated interference with cell-phone reception, further deteriorating the communications and coordination ability of the anti-China demonstrators.